Writer objects (DictWriter instances and objects returned by
the writer() function) have the following public methods. A
row must be a sequence of strings or numbers for Writer
objects and a dictionary mapping fieldnames to strings or numbers (by
passing them through str() first) for DictWriter
objects. Note that complex numbers are written out surrounded by parens.
This may cause some problems for other programs which read CSV files
(assuming they support complex numbers at all).

writerow(

row)

Write the row parameter to the writer's file object, formatted
according to the current dialect.

writerows(

rows)

Write all the rows parameters (a list of row objects as
described above) to the writer's file object, formatted
according to the current dialect.